I took level I with Dvorak last summer. It was awesome. As far as river experience goes, there is no one teaching this class that even comes close to his level of expertise. He actually is the co-author of the curriculum for the course. I was mixed in with fire personnel and he really took the time to talk on two levels. He'd say things like "If you have a truck with $100,000 worth of stuff on it, do it like this....if you're a rafter and all you have is 3 locking biners, 2 prussiks and a throw bag, do it like this."